**Figure 6. **The kinetics of the
voltage-dependent closure of gap junctional channels for homotypic (**A**,
**B**), heterotypic (**C**), and heteromeric (**D**) pairs of
RPE Cxs expressed in *Xenopus* oocytes. For homotypic pairs of
Cx43/Cx43 (**A**), the junctional current was best fit with a
second-order exponential decay, whereas homotypic Cx46 (**B**) could
be described by a single exponential function with averaged time
constants shown above (n=5 and n=3, respectively). Gating kinetics for
the heterotypic Cx43/Cx46 gap junctional channel (**C**) also
required two exponential components (n=6). Heteromeric gap junctions
(Cx43•46/Cx43•46) exhibited significantly slower gating kinetics,
requiring a second-order exponential function, with the time constants
shown in **D**, above (n=10).